Sinkhole risk in Richmond County, GA: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 79%
At or near the surface: 31%
Buried under cover: 48%

What this means before you buy

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 255 of Richmond County's 324 square miles on soluble rock, 100 of them with the rock at or near the surface. With about 206,303 residents (636 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 541 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 48% under cover still counts, and the signs to look for and how an inspection works.

Counties around Richmond County

The nearest county rated sinkhole country is Aiken County, SC, about 29 miles northeast, close enough that the same rock may run under the county line. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Columbia County, GA 17 mi northwest · 10% at surface
Burke County, GA 21 mi south · 3% at surface
McDuffie County, GA 25 mi west · 22% at surface
Aiken County, SC 29 mi northeast · 68% at surface
Jefferson County, GA 29 mi southwest · 8% at surface
Edgefield County, SC 30 mi north · 24% at surface

Which formation it is

The largest mapped soluble unit here is the Lower Tertiary-Cretaceous undifferentiated (sand), Lower Tertiary-Cretaceous in age, covering about 74% of the county. Next is the McBean Formation at 5%.

Against the rest of Georgia

Richmond County ranks 29 of 159 in Georgia for soluble rock at the surface, and sits above 80% of US counties on that measure.